Keeping carpets looking their best and extending their lifespan is simple with the right care and upkeep.

"I've only ever made a mess, and left visible marks, when I've tried to clean wall-to-wall carpeting, and I've only gotten bad advice from books and Web sites."

PAUL ISKYAN (owner, Rug Renovating): Taking care of carpet shouldn't be rocket science, but it's getting that way — there's so much misinformation out there.

Is there a kind of carpet I should have bought that wouldn't get dirty so easily?

The new carpet you'll see in houses today is 85 percent nylon, and almost all the rest is wool. Both kinds are virtually indestructible. Nylon has a little more built-in stain resistance than wool, but wool may wear a little better. After about seven or eight years, nylon fibers tend to lose their luster. We say that the carpet 'uglies out' before it wears out.

More From House Beautiful

What about the color and the pile?

The color matters less than you'd think. It's not that hard to keep white clean, and it doesn't show dust. The darker colors show every little speck. The pile doesn't matter that much, either. Cut pile is easier to clean than loop pile — the loops have more places where dirt can hide — but loop pile doesn't get matted down and crushed by traffic.

What kinds of cleaning rituals should I set up?

Take off your shoes when you get home, but leave your socks on — walking around in bare feet leaves behind natural oils that attract dirt. Vacuum every day. Use a top-load vacuum, so the dirt falls inward, and HEPA filters. Change the filters often, so you don't blow pollutants back into the air. Change the vacuum bag when it's half full, for maximum effectiveness. If you have cut pile, use a beater-bar attachment to break the surface tension and loosen dirt. But don't use it on loop pile — you don't want to break the loops.

What do I do in case of a spill?

Act quickly. Blot and blot, pushing down with a white terrycloth towel. Don't rub, or else you'll cause what we call 'nap distortion.' Don't scrub aggressively, or the nylon or wool will start to fray and twist. Keep a small handheld spot extractor around. For one that really works, expect to pay between $50 and $200. Use a little neutral soap in the extractor like Woolite, don't over-wet the spot, extract as much rinse water as you can, and dry the spot with a hair dryer. Don't be tempted to use the kind of strong stain removers you see advertised on late-night TV. They can take the color out. There is one strong chemical we do recommend — Afta dry-cleaning fluid. Use a little if you spill anything oil-based, like nail polish or tar.

How do you recommend protecting carpet from heavy furniture feet?

It's not so much the indentations you should be concerned about, it's the wear and tear from chairs being moved around a lot. Above all we recommend putting a plastic chair mat under your desk chair.

Will padding extend the carpet's lifespan?

Absolutely. Padding absorbs shocks. You especially want it on stairs, where the carpet has to take a lot of pounds per square inch.

Are there different cleaning methods for the different kinds of carpet fibers?

Always clean with hot-water extraction. That means bringing in professionals to prespray the carpet, agitate it to loosen the dirt, work in the soap, and really rinse and extract the wastewater. Any treatment less thorough will leave behind a soapy film, which will dry and then keep cleaning the bottoms of the shoes and feet of everyone who walks past — leaving dirt that adheres to the carpet.

Is it okay to clean with one of those shampooing machines you can rent?

Worst mistake you could make.

How do I choose a good cleaning service?

You want one that's not just some guys with a Web site and a truck, but a reputable company with insurance and some IICRC qualifications — that stands for Institute of Inspection, Cleaning and Restoration Certification [certifiedcleaners.org]. And make sure that the staff can answer technical questions, like what's the maximum pH you'll use in a cleaning solution? If they don't know, or if it's a number higher than 10 for nylon or 8.2 for wool, then your carpet is at risk of being ruined. And you should expect to pay between 50 cents and $1 per square foot for cleaning. Anyone giving you a lower estimate is probably just going to inject cleaning solution into the carpet, not fully extract it, and leave soap behind.

How often should I call in the professionals?

The most often you'd need would be three or four times a year, for a room heavily used by young kids. The less trafficked areas can be cleaned once or twice year, and you could get away with every 18 months for a bedroom. Once you see that your carpet's dirty, you probably should have it cleaned. Not mainly for the appearance, but for health reasons — getting rid of dust, mold, bacteria, and mildew, the pollutants that get trapped in soft surfaces.